Four more suspected cases of a mysterious bird flu that has killed at least three people have surfaced in Hong Kong, officials said Thursday, while blood samples drawn from hundreds of local poultry have turned up no clues.
Doctors so far have detected nine people with the A H5N1 poultry virus, while 10 others are believed to be infected. Three of the confirmed cases have died, along with one of the suspected cases.
There is no vaccine, and doctors don't know how people are catching it. Prior to this outbreak, the virus had been seen only in birds.
Wednesday, the government halted all chicken imports from China in an attempt to prevent the spread of the flu and scrubbed down Hong Kong's main poultry markets. About 75,000 chickens, or 70 percent of those sold in Hong Kong daily, are imported from the Chinese mainland.